A quartz timepiece such as a quartz clock is known to use an electronic oscillator that is regulated by a quartz crystal for timekeeping. This crystal oscillator creates a signal with very precise frequency, so that the quartz clock is at least in an order of magnitude and more accurate than mechanical clocks. Generally, a digital logic counts the cycles of this signal and provides a numeric time display in the format of hour, minute and second. Quartz timepieces are the most common technology of timekeeping in available clocks and watches as well as in computers and other appliances that keep time.
A radio controlled (RC) clock is the type that is synchronized by a time code bit stream transmitted by a radio transmitter connected to a time standard such as an atomic clock. The RC clock may be synchronized to the time sent by a single transmitter, such as many national or regional time transmitters, or may use multiple transmitters, like Global Positioning System. These systems can be used to set computer clocks or clock means for human readability, or for any purpose where accurate time is needed. The RC clocks synchronized to terrestrial time signals can achieve an accuracy of around 1 millisecond relative to the time standard, but are generally limited by uncertainties and variability in radio propagation.
Generally a clock can display the time by an analog clock display, a digital clock display, or both. The analog clock display includes an hour hand, a minute hand, and a second hand to display the time. The digital clock display displays the time digitally. Some markings or labels may be included on the display for example to indicate that the clock is radio controlled. The analog clock display has a clock face similar to traditional mechanical clocks, and is more popular than the digital display to some people.
A RC clock of analog display generally comprises a receiving antenna and a receiving circuit, a MCU or CPU processor, driving motors comprising a second hand motor and an hour hand and minute hand motor, gears comprising a second hand gear, a minute hand gear and an hour hand gear, and hands alignment means comprising a photoelectric transmitter and a photoelectric receiver controlled by the CPU processor which are respectively arranged above the second hand gear and below the hour hand gear. Each of the second hand gear, the minute hand gear and the hour hand gear is formed with locating holes for the purpose of time-correction.
During the synchronization process, especially for the first time when the clock is powered on, the analog RC clock aligns all hands at 12 o'clock, receives a RCC (radio controlled clock) signal from a designated RCC station having a matchable frequency through its receiving antenna and receiving circuit, decodes the signal to obtain the correct time by the MCU/CPU, then moves the hands from 12 o'clock to the respective positions indicating the correct time. For time-correction of the hands, all the hands must be positioned at “12” o'clock, and the locating holes formed on the gears should be aligned with each other until the synchronization is successfully completed by the alignment means. Namely, the light emitted by a photoelectric transmitter must simultaneously pass through all the locating holes on the respective gears and be received by the photoelectric receiver.
It takes a very long time for completing the synchronization process, which costs about a few minutes, since the hands of the analog RC clock is driven by the motors through the different gears, and both the time needed for the hands returning back to the 12'oclock for time-correction and the time needed for the hands going to the respective correct positions are quite long. Therefore it will be advantageous if time synchronization or time correction can be reduced. Moreover, cost of manufacturing the movement of the analog RC clock is high because of expensive components such as gears and drive coils which require to be machined precisely.
In some occasions, it is not required for time-correction of the second hand, the minute and the hour hand at the same time, and it is possible that only the position of second hand needs to be corrected.
Therefore, there is a need for providing a method for time-correction of an analog quartz timepiece which is not expensive and independent of the gears, and by which the second hand, the minute and/or the hour hand can be corrected separately.